Swimming pool cleaning method and apparatus

ABSTRACT

A swimming pool cleaning apparatus comprising a quick connect-disconnect handle, an ovate frame, a collecting net structure with an inner and outer section, and a blade-like edge on the forward portion of the frame. The collecting net structure contains an open inner net contained in a closed outer net; the inner net allows easy ingress of debris into the outer net while retarding its escape if the direction of net motion is reversed. The blade-like edge of moderately flexible material attached to the front of the net increases the efficiency of collection of debris close to the bottom walls of the pool. Construction of the apparatus is modular and allows easy replacement of worn parts without discarding serviceable parts; repairs can be made without the use of tools. The ease of assembly and disassembly allows the net to be stored and shipped in a disassembled state and is reflected in reduced handling costs.

TECHNICAL FIELD

This invention relates to devices for cleaning swimming pools, spas,decorative pools, and similar bodies of water, and in particular to"leaf rakes" for removing leaves and other debris from the submergedsurfaces of pool structure, i.e. pool bottoms, step surfaces and slopingwalls: it also relates to "skimmers" which are used for collectingfloating debris.

BACKGROUND ART

Cleaning nets like "leaf rakes," herein defined as nets whose depth ofcollecting pouch is about equal to or about twice as great as thesmallest dimension of the opening into the net, and "skimmers," whichare similar but have a shallower net, have been in use for many years.Although they may vary somewhat in size and shape, leaf rakes andskimmers have common structural features. One feature is that nettingmaterial is usually attached to the frame by wrapping it around theframe and applying a conformal metal or plastic cover sheath whichsecures the net to the frame and protects it from abrasion during use.Since netting material has a relatively short life, due to mechanicalwear and the action of sunlight and water chemicals, it requiresfrequent replacement. As existing nets are designed, netting replacementby the end user is usually difficult because the netting must be held ina precise relationship to the frame with one hand while the cover sheathis attached with the other. Often, special tools are required, or theentire net must be replaced or returned to the manufacturer for repair.This net replacement problem has been addressed specifically in U.S.Pat. No. 4,169,331 which describes a net which is relatively easy toreplace. However, fastening the net to the frame by means of a veryspecial plastic frame cover to which the net is secured by a moldingprocess is inherently expensive. The net fastening method described inU.S. Pat. No. 3,220,037 is a simpler, less expensive solution butrequires considerable skill and/or special tools to accomplish the task.Another feature is that the rigid, net-supporting frame is permanentlyassembled to the short handle that is used for quick connect-disconnectattachment of the net to a long extension pole. If the frame isaccidently bent or otherwise damaged, for example, in many cases theentire assembly including the frame and its short attachment handle mustbe replaced. An attempt to alleviate the handle problem is presented inU.S. Pat. No. 2,706,664 wherein a simple method of assembling a framewith round cross-section is shown. However, it is not easily adaptableto frames of rectangular or girder shaped cross-section. The assemblymethod shown for a frame of rectangular cross-section in U.S. Pat. No.3,220,037 not only requires special tooling for assembly but alsoresults in a high stress point at the sharp corners where the frameenters the handle.

In addition to the problems of netting and parts replacement resultingfrom the design features of existing nets, there are operationaldifficulties arising from features omitted from their design. Onedeficiency of existing leaf rakes is that there is no provision to keepleaves and debris from coming back out of the net as it is pushed along,resulting in lost time for pool servicemen. U.S. Pat. No. 4,003,100describes a net structure intended to retain collected debris duringuse. The form of this net with its rigid entry member and nominallyvertical orientation of net opening does not lend itself well to mostpool cleaning applications because the form of underwater pool surfacesrequires some flexibility and curvature of the net entrance lip. Anothercommon deficiency is that the edge of the net where it contacts the poolsurfaces is generally round or blunt, thus making it difficult to coaxleaves very close to the bottom of the pool into the net. An example ofa special edge structure which has a lip designed to capture debrisadhering to pool wall surfaces is given in U.S. Pat. No. 3,220,037. Thedifficulty with this device is that the net must be inverted in orderfor the lip to work effectively. Another design feature common to mostexisting nets is that they are manufactured as permanent assemblieswhich cannot easily be disassembled or assembled in the field.Therefore, they must be shipped and stored in larger, space consumingcontainers than would be required if they could be broken down into amore compact package.

DISCLOSURE OF INVENTION

The collection net apparatus of the present invention, as applied toboth leaf rakes and skimmers, provides for easy replacement of nettingas well as all other parts of the net, by using a modular designrequiring no tools for assembly. For leaf rakes, the addition of asecondary inner net and a front cover blade to the basic net structureinsures that leaves and debris are much more effectively gathered andretained in the net structure of this invention than in existing nets.The modular design and ease of assembly make it practical to store andship nets in a disassembled condition, thereby reducing handling costs.

Accordingly, it is an object of this invention to improve the collectingefficiency of a swimming pool cleaning net by trapping collected debrisuntil the net is deliberately emptied, and to provide a blade-like frontedge on the net to enhance the ability of the person handling the net topick up debris close to the bottom of the pool.

A further object of this invention is to provide an inexpensive netstructure that is assembled from modular components common to both leafrakes and skimmers in such a way that any part can be replaced withsimple tools, or with no tools at all, without the necessity ofdiscarding any other parts which are still useful.

A still further object of this invention is to provide a net structurethat requires less storage space and a smaller shipping container thanexisting nets of comparable capacity.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of the pool net described herein;

FIG. 2 is a top view of the pool net described herein;

FIG. 3A is a cross-section of the net taken along line 3--3 in FIG. 2showing the inner net for trapping debris in the open position;

FIG. 3B is the same cross-section as in FIG. 3A but with the inner netin the closed position with arrows showing the direction of motion ofthe net, and omitting background detail for clarity;

FIG. 4 is a perspective view within the line 4 of FIG. 1 with cut-awaysections showing the frame held in the detachable handle, the nettingaround the frame, the frame cover and the reclosable seam of the innernet;

FIG. 5 is a cross-section of the frame, the detachable net looped overthe frame, and the rear portion of the protective cover taken along line5--5 in FIG. 2;

FIG. 6 is a cross-section of the frame, detachable net and centerportion of the cover blade taken along line 6--6 in FIG. 2;

FIG. 7 is a cross-section of the frame and detachable handle taken alongline 7--7 of FIG. 2; and

FIG. 8 is an exploded perspective end view of the detachable handletaken inside the line 8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, the perspective view of FIG. 1 shows theimproved net structure designated generally by 10; an extension pole 12to which the net attaches during use is shown for reference. Acollecting net consisting of a pouch-like section 13 dependsperpendicularly from frame 16 and is protected from abrasion by coverpieces 18, 19 and 20. In the case of the leaf rake, an inner section 14,which functions as a debris trap, and a blade-like front edge 18, areadded to increase the efficiency of underwater operations. All otherstructural features are common to both the leaf rake and the skimmer.Each component of the net structure will now be described in detail withemphasis on the leaf rake since it is slightly more complicated due tothe addition of the inner net 14 and the cover blade 18.

With reference to FIGS. 1 through 4, the netting configuration for leafrakes is shown to consist of a single piece of foraminous material suchas fine nylon mesh. This single piece of netting material is formed intoan outer section 13, made as a pouch with permanent seams 24 and 25, andis folded over frame 16 re-entrantly into outer section 13 to form theinner section 14 which functions as a debris trap. The inner and outersections are secured to frame 16 by means of reclosable fastener strips17 attached to outer section 13, and 21 attached to inner section 14, soas to be closely parallel to frame 16 and become mating pieces when thenetting is folded over frame 16. The inner section 14 is formed into anopen-ended, reclosable cylinder by pressing together strips 22 and 23 toform seam 27. lnner section 14 is tapered so that the open end oppositeframe 16 is smaller in perimeter than the outer section 13 and whenproperly in place is shorter than the outer section 13. In the preferredembodiment, said open end of the inner net 14 tapers to a perimeterabout fifty percent of the perimeter of the other end; the depth ofinner net 14 is about sixty to eighty percent of the depth of outer net13. A rectangular cutout 26 in the netting material provides clearancefor handle 11. Although the preferred embodiment utilizes reclosableseams to facilitate quick netting replacement, it should be readilyapparent that the net structure consisting of outer section 13 and innersection 14 could as easily be made with permanent seams withoutdeparting from the spirit of this invention. In the case of skimmers,only outer net 13 is used and may have the same permanent seams 24 and25 forming the pouch. No inner net 14 is required, so the nettingmaterial merely wraps around frame 16 as shown in FIG. 4, and isattached with reclosable fastener strips 17 and 21 with the insidenetting material terminating at fastener strip 21. As with the leafrake, the reclosable seam made of fastener strips 17 and 21 could bereplaced with permanent seams. A special case of skimmer netting obtainsfor very shallow skimmer nets wherein netting material only slightlylarger than frame 16 is bordered with a cloth loop around frame 16formed by reclosable fastener strips like 17 and 21, or with permanentseams.

The shape of frame 16, as shown in FIGS. 1 and 2, can be applied to bothleaf rakes and skimmers. In the case of skimmers, length to widthratios, corner angles, and degree of curvature of side sections of thenet are not critical and can be easily adjusted to various sized pools.In the case of leaf rakes, however, the shape of the frame is morecritical. Therefore, the following discussion pertains primarily toframes for leaf rakes. In the preferred embodiment, frame 16 supportingthe netting material is made from a single length of suitable materialformed into the general ovate shape shown in FIG. 2, wherein the corners28 and 29 are bent to an angle between 70 and 110 degrees. The forwardportion opposite the support end and between said angles is of arcuateshape such that the ratio of the chord of the arc to its sagitta isbetween about ten and twenty to one. Operating experience with this netstructure has shown that the width (transverse axis) of the frame 16should be about two to three times its length for proper operation ofthe debris trap. In the preferred embodiment, the frame is made ofaluminum of 1/8 inch by 1/2 inch cross-section, as shown in FIG. 5.Other materials such as plastic, steel, or stainless steel may also beused, and in various cross-sections from circular to girder shapes, i.e.curved, I-beam or C channel, depending upon the rigidity desired. FIG. 4illustrates the configuration of the frame as it is clamped in grooves40 in the quick connect-disconnect handle indicated generally as 11.wherein each end of frame 16 is bent at right angles. both to preventlateral movement and to increase the vertical rigidity of frame 16.

Quick connect-disconnect handle 11 is shown in FIG. 4 to be made of twoidentical halves 30 and 31 and is made, for example, of die castaluminum or injection molded plastic of suitable rigidity such asurethane. Only one mold configuration is needed to make both pieces 30and 31, thus reducing production, stocking, and assembly costsconsiderably from what they would be with two different parts. Thecylindrical portion of the handle, formed when 30 and 31 are assembled,is of the same diameter and length to match other interchangeable poolcleaning implements and contains a common spring-actuated locking device32 for holding it in place in pole 12. Two bolts held non-rotatably bycontoured recesses in 30 and 31 clamps said halves together tightlywithout the use of tools when wing nuts 34 are tightened. While boltsand wing nuts are used in the preferred embodiment, it is readilyapparent to those skilled in the art that other easily actuatedfastening devices, such as wire pins, self-locking rings, speed nuts, orspring clamps, may be used without departing from the spirit of thisinvention. The thicknesses of the flat, clamping areas 41 of handleparts 30 and 31 that hold frame 16 are reduced slightly at the innersurfaces so that a space 35 obtains to insure that the total clampingforce of bolts 33 is transferred to frame 16. Since handle parts 30 and31 completely enclose the right angle bends in frame 16, they act asstrain reliefs to remove repeated bending stresses, occuring during use,from the already highly stressed bend area; operating experience withexisting nuts has shown that most frames fail at these vulnerablepoints. The end of handle 11 opposite frame 16 is shown in an explodedperspective view in FIG. 8 taken inside line 8 of FIG. 7. Interlockinggrooves 36 and 39 and projections 37 and 38 prevent lateral shifting of31 with respect to 30. The shape and position of said grooves andprojections, which in the preferred embodiment are rectangular incross-section, are symmetrically located about the vertical centerlineand are inverted about the horizontal centerline. Other lockinggeometries which preserve the ability to assemble two halves made fromthe same mold (such as a saw tooth or pin and hole) are all within thescope of this invention.

The netting material where it loops over frame 16 must be protected fromabrasion during use. The most common method of doing this is to utilizean extruded plastic cover piece (similar to 19 in FIG. 5) which, inexisting nets, both protects and clamps the netting to its frame. Inthis invention, since the netting is already secured to the frame 16 byseams, only abrasion protection is needed. This abrasion protection canbe provided all around the net and frame periphery by such a cover 19which, since it need hold only itself in place, may be more flexible andof lighter weight material than that used in existing nets. Skimmersrequire only such netting protection as cover 19 and, therefore, utilizeonly the simple form of protective coating shown in FIG. 5. However, inthe case of leaf rakes, abrasion protection can be obtained while at thesame time improving the debris gathering efficiency of the net by usinga formed cover blade 18 with the blade-like, nominally triangularcross-section shown in FIG. 6 for the front part of the protectivecover. The horizontal contour of this cover, matching as it does thearcuate contour of frame 16, allows the net 10 to follow pool bottomseasily since most submerged pool surfaces have gently curving contours.The sloping surface 42 of cover blade 18 directs debris efficiently intothe net. It should be noted that, although the cross-section of coverblade 18 is a solid right triangle in the preferred embodiment, planarsurface 42 may vary from moderately concave to moderately convex. Thebase 43 of the nominally triangular cross-section of cover blade 18 inthe preferred embodiment is perpendicular to the plane of frame 16 andthe altitude of said cross-section is parallel to the plane of frame 16.However, it is readily apparent to those skilled in the art that othercross-sectional configurations which may include material deletions forreducing weight and which adequately clamp the cover blade to the framewhile still providing for a functional, sharp-edged ramp forward offrame 16 are also within the scope of this invention. Extending thistriangular cross-section around corners 28 and 29 of frame 16 allows thenet to reach corners such as those found at steps and underwater seats.Cover blade 18 may be made of the same material as covers 19 and 20 butshould be flexibly deformable at the outer, pointed edge of the blade soas to conform easily to irregularities in pool surfaces and yet beelastic enough to return to its original shape; in addition, it must bequite resistant to abrasion. Low durometer urethane is ideally suited tothis application, but other materials of appropriate physical propertiesmay be used. The remaining two portions of frame 16 not enclosed bycover blade 18 can be protected by the same lightweight, extruded coverpieces 19 and 20 having the cross-section used for protecting skimmernets as shown in FIG. 5.

Having thus discussed the various components of leaf rakes and skimmersin this invention, their overall operation will now be described.Skimmers, as described in this invention, are improved by virtue oftheir modular construction as are the leaf rakes, but otherwise functionlike existing skimmers as surface scoops. The leaf rakes describedherein, however, have an operational advantage over existing leaf rakesbecause of the addition of cover blade 18 and debris trap 14 to thebasic net structure. During the pool cleaning operation, net 10,attached to pole 12, is pushed along the bottom surfaces of pools withthe front edge of cover blade 18 in contact with the bottom and theplane of frame 16 of the net inclined to the surface being cleaned at anangle varying from 20 to 70 degrees. Over this range of attitudes thecombination of the flexibility of cover blade 18 and resiliency of thearcuate portion of frame 16 optimizes contact of cover blade 18 withpool surfaces and greatly increases the capture efficiency of the netfor debris. At the end of the forward motion (in the direction of thepole), the net is usually lifted somewhat and is moved in the directionshown by the arrow in FIG. 3A, at which time captured litter goes to thebottom of the outer section 13 if it has not done so already. To start asecond cleaning stroke, the motion of the net is often reversed, asshown in FIG. 3B. Now the water moving through the outer section 13 andinner section 14 tends to wash material out of the outer section 13, butsince the direction of water flow reverses, the inner section 14 tendsto close; previously gathered material in outer section 13 thereforewill be prevented from escaping. The corners 28 and 29 of cover blade18, being close to 90 degrees, facilitate removal of debris from thecorners of steps and shelves in the pool.

ln addition to the unique performance that can be realized with thisimproved leaf rake structure, there also are savings in time and moneyeffected by the modular construction which applies to both the leaf rakeand skimmer. Nets, being working tools, are subject to the usual wearand tear encountered in use, plus accidental breakage such as mightoccur when transporting nets from pool to pool in commercial operations.It is possible to replace the netting and any part or parts of these netstructures, if necessary, without replacing remaining serviceable parts,and to do so without using any tools whatsoever. For example, the coverblade 18 and cover pieces 19 and 20 are replaced by prying the oldpieces off by hand and snapping new ones into place. To replace thenetting, it is only necessary to take off the cover pieces, as above,open the reclosable seams to remove the old netting, and replace the newnetting material and cover pieces in the reverse order. Similarly, theframe may be disassembled and replaced by removing the covers and net asabove and, in addition, loosening the two wing nuts to allow handle 11to come apart to release the frame. Even in the case of nets made withpermanent seams, net replacement requires only disassembly of the net asdescribed above, including removing frame 16. Frame 16 is then threadedthrough the cloth loop formed by the permanent seam and then reassembledas before.

In addition to the improved operation of net 10, its ease of repair, andits savings in parts, the fact that the net can be disassembled soeasily allows it to be stored and shipped in the disassembled state,thus bringing economies into the warehousing, shipping, and retailing ofthe net by requiring less storage space and smaller shipping containersthan its fully assembled coun- terpart.

Having thus described two embodiments of this invention which form afamily of nets by virtue of the commonality of parts used throughouteach embodiment, it is to be understood that minor changes in shape,size, or materials which do not depart from the spirit of this inventionwill be apparent to those skilled in the art, given the teaching herein.

I claim:
 1. A collecting net apparatus for swimming pools and the likecomprising:a planar, ovate frame symmetrical about the short orlongitudinal axis of said ovate shape and having a transverse axissubstantially longer than said short axis, a convex arcuate forwardportion with chord parallel to said transverse axis, each end of saidforward portion formed into an angle close to 90 degrees and proceedingrearward to complete the ovate shape and terminating in short endsprojecting rearwardly, parallel to said short axis, said frame beingmoderately resilient along said short axis but substantially rigidnormal to said plane; a net formed from a single piece of foraminousmaterial into an outer cylinder with one end closed to form a pouch,said outer cylinder passing outwardly of said frame and folded inwardlyover said frame to form a reentrant, open-ended inner cylinder, saidinner cylinder tapering so that the end of said inner cylinder oppositesaid frame is smaller in perimeter than said outer cylinder and saidinner cylinder is shorter than said outer cylinder, said inner and outercylinders being loosely secured to said frame by a seam adjacent to andparallel to said frame, both of said cylinders depending perpendicularlytherefrom; a protective cover of three portions easily attached oversaid frame and said folded net and conforming thereto having a centerblade-like portion covering said arcuate forward portion of said frameand extending far enough beyond each end of said arcuate forward portionto cover said angles, and two separate rear portions with tubularcross-section covering rearward portions of said frame and said foldednet; and a handle assembled from two mating, identical pieces, saidhandle firmly holding said short ends of said frame by the clampingaction of easily actuated fasteners projecting through both said matingpieces, said fasteners held non-rotatably by contoured recesses in saidmating pieces, and said mating pieces having interlocking projectionsand mating recesses on the end of said handle opposite said fasteners.2. A collecting net apparatus as in claim 1 wherein the length of saidchord of said convex forward portion is ten to twenty times the sagittaof said arcuate portion and said angle is between 70 and 110 degrees. 3.A collecting net apparatus as in claim 1 wherein said net is secured tosaid frame by reclosable fastener strips attached to said inner andouter cylinders adjacent to and parallel to said frame and additionallyhaving a reclosable seam forming said inner cylinder.
 4. A collectingnet apparatus as in claim 1 wherein said center blade-like cover has anominally triangular cross-section, said cross-section having analtitude substantially longer than the base of said triangle, saidaltitude lying parallel to the plane of said frame, and the vertexopposite said base forming the edge of said blade forward of said frame.5. A method for increasing the collection efficiency of a collecting netapparatus used to collect debris from a pool surfacecomprising:disposing an open-ended inner net within a closed outer netto form a composte net structure, said closed outer net passingoutwardly of a planar, ovate frame, said frame being symmetrical aboutthe short or longitudinal axis and having a transverse axissubstantially longer than said short axis, said closed outer net foldinginwardly over said frame to form a re-entrant, open-ended innercylinder, said inner cylinder tapering so that the end of said innercylinder opposite said frame is smaller in perimeter than said outercylinder and said inner cylinder is shorter than said outer cylinder,said inner and outer cylinders being loosely secured to said frame by aseam adjacent to and parallel to said frame, both of said cylindersdepending perpendicularly therefrom such that said inner net allows easyingress of debris into said closed outer net upon forward motion of thecomposite net structure but retards egress of said debris from saidclosed outer net when the direction of motion of said composite netstructure is reversed; and applying a flexible, cover-blade over thearcuate forward portion of said ovate frame and extending far enoughbeyond each end of said arcuate section to cover the angular ends ofsaid frame, said cover-blade having a sharp but moderately flexibleforward edge which is parallel to and in the same plane as said frameand which flexibly adjusts to the contour of the pool surface beingcleaned so that, upon forward motion of said collecting net apparatusacross said pool surface to collect said debris, debris adhering to saidpool surface is scraped off, thus facilitating ingress of debris intosaid collecting net apparatus.